1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to home device control in a home network, and more particularly, to methods and apparatuses and articles of manufacture for exclusively controlling a controlled device in a universal plug and play (UPnP) network.
2. Description of Related Art
A universal plug and play (UPnP) network includes a controlled device, that is, a home device which is connected to an Internet Protocol (IP) based home network and a control point which controls the controlled device.
FIG. 1 is a view showing the construction of a general UPnP network.
The example shown in FIG. 1 is a UPnP audio-visual (AV) system which is based on a UPnP device architecture. In the UPnP AV system, a control point (CP1) 101 and a control point (CP2) 102 perform discovery, description, control, and eventing operations according to the UPnP standard in order to control a media server 103 and a media renderer 104 which are controlled devices. Since the operations are described in the context of well-known UPnP standard, detailed description thereof is omitted.
In the UPnP AV system, the media server 103 and the media renderer 104 are controlled non-exclusively by both the control point (CP1) 101 and the control point (CP2) 102. Accordingly, as seen by either of the control points, the media server 103 or the media renderer 104 may change into an undesirable state.
FIGS. 2A and 2B are views for explaining a conventional system for exclusively controlling a controlled device. As an example of solving the aforementioned problem, the system shown in FIGS. 2A and 2B is disclosed in Korean Patent Publication Application No. 10-2004-55455.
As shown in FIG. 2A, in the conventional system, a look-up server is installed in a home gateway, and the look-up server manages a look-up table shown in FIG. 2B. The look-up table stores a list of controlled devices residing in the current network, control status of the controlled devices, and names of control points controlling the controlled devices.
When the control point CP1 controls the controlled devices residing in the current network, the look-up table shown in FIG. 2B is constructed. At this time, if the control point CP2 participates in the current network to control the devices, the home gateway transmits information on the control status of the associative devices to the control point CP2 with reference to the look-up table. Therefore, the control point CP2 is notified of the control status of the associated devices before the control point CP2 starts controlling the associated devices.
However, in the conventional system, a look-up server managing the look-up table must be separately installed. Accordingly, the look-up server may be a burden in the system. Even though the look-up server is installed, if another control point tries to forcibly control the controlled device without complying with the procedure discussed above, it is difficult to prevent such a control point from interfering with the controlled device. Therefore, there is a problem in that it is substantially impossible to prevent a plurality of control points from controlling the controlled device in an interfering manner.